Nimet Baltas

Phenolic components, antioxidant activity, and mineral analysis of Capparis spinosa L

In addition to being consumed as food, caper ( Capparis spinosa L.) fruits are also used in folk medicine to treat inflammatory disorders, such as rheumatism. C. spinosa L. is rich in phenolic compounds, making it increasingly popular because of its components’ potential benefits to human health. We analyzed a number of individual phenolic compounds and investigated in vitro biological activities of C. spinosa L. Sixteen phenolic constituents were identified using reverse phase-high performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity were used as determinants of antioxidant capacity. C. spinosa L. exhibited strong antioxidant activity and contained high levels of antioxidant compounds. Gentisic, sinapic and benzoic acid were detected in C. spinosa L. No gallic acid, proto -catechuic acid, proto -catechuic aldehyde, chlorogenic acid, p -OH benzoic acid, vanillic acid, caffeic acid, syringic acid, vanillin, syringaldehyde, p -coumaric acid, ferulic acid or rosmarinic acid were identified. Iron and zinc were present at high levels in samples. C. spinosa L. appears to be a good source of antioxidants and minerals that might serve to protect health and combat several diseases. Key words : Antioxidant, capers, Capparis spinosa L., phenolics.

Polyphenol oxidase activity and antioxidant properties of Yomra apple (Malus communis L.) from Turkey

Abstract In this study, firstly, antioxidant and polyphenol oxidase (PPO) properties of Yomra apple were investigated. Seventeen phenolic constituents were measured by reverse phase-high-performance liquid chromatography (RP-HPLC). Total phenolic compounds (TPCs), ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activities were performed to measure antioxidant capacity. Some kinetic parameters (Km, Vmax), and inhibition behaviors against five different substrates were measured in the crude extract. Catechin and chlorogenic acid were found as the major components in the methanolic extract, while ferulic acid, caffeic acid, p-hydroxybenzoic acid, quercetin and p-coumaric acid were small quantities. Km values ranged from 0.70 to 10.10 mM in the substrates, and also 3-(4-hydroxyphenyl) propanoic acid (HPPA) and L-DOPA showed the highest affinity. The inhibition constant of Ki were ranged from 0.05 to 14.90 mM against sodium metabisulphite, ascorbic acid, sodium azide and benzoic acid, while ascorbic acid and sodium metabisulphite were the best inhibitors.

Inhibition properties of propolis extracts to some clinically important enzymes

Abstract The present study was conducted to envisage inhibition effects of propolis on the crucial enzymes, urease, xanthine oxidase (XO) and acetylcholinesterase (AChE). Some of the antioxidant properties of the propolis samples were determined using the total phenolic content (TPE) and total flavonoids in the eight different ethanolic propolis extracts (EPE) samples. Inhibition values of the enzymes were expressed as inhibition concentration (IC50; mg/mL or μg/mL) causing 50% inhibition of the enzymes with donepezil, acetohydroxamic acid and allopurinol as reference inhibitors. All the propolis extracts exhibited variable inhibition effects on these enzymes, but the higher the phenolic contents the lower the inhibitions values (IC50 = 0.074 to 1.560 mg/mL). IC50 values of the P5 propolis sample having the highest TPE, obtained from Zonguldak, for AChE, urease and XO were 0.081 ± 0.009, 0.080 ± 0.006 and 0.074 ± 0.011 μg/mL, respectively. The EPE proved to be a good source of inhibitor agents that can be used as natural inhibitors to serve human health.

Synthesis and antioxidant activities of some new triheterocyclic compounds containing benzimidazole, thiophene, and 1,2,4-triazole rings

Abstract Various triheterocyclic compounds containing benzimidazole, thiophene, and 1,2,4-triazole rings (3–6) were synthesized and screened for their antioxidant activities. The structures of the synthesized compounds (2–6) were judged by 1H NMR, 13C NMR, elemental analysis, and LC-MS spectral data. Antioxidant activities of the synthesized compounds (2–6) were determined with CUPric Reducing Antioxidant Capacity (CUPRAC), ABTS (2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)/persulfate, and DPPH (1,1-diphenyl-2-picrylhydrazyl) assays. Most of the compounds showed a significant antioxidant activity and especially, compound 5c showed very good SC50 value for DPPH method and compound 5h exhibited very high scavenging activity to ABTS method.

Effect of propolis in gastric disorders: inhibition studies on the growth of Helicobacter pylori and production of its urease

Abstract There is considerable interest in alternative approaches to inhibit Helicobacter pylori (H. pylori) and thus treat many stomach diseases. Propolis is a pharmaceutical mixture containing many natural bioactive substances. The aim of this study was to use propolis samples to treat H. pylori. The anti-H. pylori and anti-urease activities of 15 different ethanolic propolis extracts (EPEs) were tested. The total phenolic contents and total flavonoid contents of the EPE were also measured. The agar-well diffusion assay was carried out on H. pylori strain J99 and the inhibition zones were measured and compared with standards. All propolis extracts showed high inhibition of H. pylori J99, with inhibition diameters ranging from 31.0 to 47.0 mm. Helicobacter pylori urease inhibitory activity was measured using the phenol-hypochlorite assay; all EPEs showed significant inhibition against the enzyme, with inhibition concentrations (IC50; mg/mL) ranging from 0.260 to 1.525 mg/mL. The degree of inhibition was related to the phenolic content of the EPE. In conclusion, propolis extract was found to be a good inhibitor that can be used in H. pylori treatment to improve human health.

Evaluation of Anti-Helicobacter Pylori Activity and Urease Inhibition by Some Turkish Authentic Honeys

Infection with Helicobacter pylori (H. pylori) is an important known risk factor for gastric disease. At least half the world’s population is under the influence of this bacterium type. So many therapeutic studies focus on treat gastric disease. But these treatments could be interrupted due to metabolic toxic and show the drug resistance. The objective of this study was to investigate the effecting degree of H. pylori with different type of honey samples from Turkey. The study was supported by bioactivity results of total phenolic (TPC) and flavonoid content (TFC). The agar-well diffusion assay was carried out on H. pylori strain J99 and the inhibition zones were measured and compared with standards. Inhibition of H. pylori urease as IC50 ranged from 2.67-18.12 mg/mL. These results were supported by TPC and TFC had range from 22.10-79.00 mg Gallic Acid Equivalent (GAE)/100 honey and 0.88-7.08 mg Quercetin Equivalent (QE)/100 g honey, respectively. These results indicate that honey extracts may be appropriate agents to treat H. pylori by inhibition effect.

Investigation of a wild pear species (Pyrus elaeagnifolia subsp. Elaeagnifolia Pallas) from Antalya, Turkey: polyphenol oxidase properties and anti-xanthine oxidase, anti-urease, and antioxidant activity

ABSTRACT Polyphenol oxidase properties and anti-xanthine oxidase, anti-urease, and antioxidant activity were investigated in Pyrus elaeagnifolia subsp. elaeagnifolia Pallas harvested from Antalya, Turkey. Optimum pH and temperature were 7.0 and 30°C, respectively. Selected kinetic properties of polyphenol oxidase was evaluated.The Km and Vmax-values, using 4-methylcatechol as substrate, were calculated as 3.57 mM and 4781 U/mg protein, respectively. IC50-values ranged from 0.0036 to 4.0231 mM against sodium metabisulphite, ascorbic acid, sodium azide, and benzoic acid, while ascorbic acid was the strongest inhibitor. Aquatic extracts of the sample exhibited strong antioxidant capacity and substantial xanthine oxidase and urease inhibition, with IC50-values of 10.75 ± 0.11 and 0.97 ± 0.03 mg/mL, respectively.

Partial purification and characterization of lipase from Geobacillus stearothermophilus AH22

Abstract The lipase was partially purified by ion exchange chromatography and gel filtration column chromatography, and was characterized from Geobacillus stearothermophilus AH22 strain. The lipase was purified 18.3-folds with 19.7% recovery. The lipase activity was determined by using p-nitrophenyl esters (C2–C12) as substrates. The Km values of the enzyme for these substrates were found as 0.16, 0.02, 0.19 and 0.55 mM, respectively, while Vmax values were 0.52, 1.03, 0.72 and 0.15 U mg−1. The enzyme showed maximum activity at 50 °C and between pH 8.0 and 9.0. The enzyme was found to be quite stable at pH range of 4.0–10.0, and thermal stability between 50 and 60 °C. It was found that the best inhibitory effect of the enzyme activity was of Hg2+. The inhibitory effect as orlistat, catechin, propyl paraben, p-coumaric acid, 3,4-dihydroxy hydro-cinnamic acid was examined. These results suggest that G. stearothermophilus AH22 lipase presents very suitable properties for industrial applications.

Purification and characterization of extracellular α-amylase from a thermophilic Anoxybacillus thermarum A4 strain

ABSTRACT α -Amylase from Anoxybacillus thermarum A4 was purified using ammonium sulphate precipitation and Sephadex G-100 gel filtration chromatography, with 29.8-fold purification and 74.6% yield. A4 amylase showed best performance for soluble potato starch hydrolysis at 70 °C and pH 5.5-10.5. A4 amylase was extremely stable at +4 °C, and the enzyme retained over 65% of its original α - amylase activity at 70 °C and 43% at 90 °C. The enzyme’s K m values for soluble starch, amylopectin and amylose substrates were obtained as 0.9, 1.3 and 0.5 mg/mL, respectively. EDTA, Hg 2+ , B 4 O 72- , OH - , CN -, and urea exhibited different inhibition effects; their IC 50 values were identified as 8.0, 5.75, 16.5, 15.2, 8.2 and 10.9 mM, respectively. A4 amylase exhibited extreme stability toward some surfactants and perfect match for a wide variety of commercial solid and liquid detergents at 55 °C. So, it may be considered to be potential applications for detergent and other industrial uses.

Synthesis, Antioxidant, Xanthine Oxidase and Urease Inhibitory Activities of Some Chlorine Containing Benzimidazoles

Bir seri tetra-substitüe benzimidazol türevi sentezlendi ve üreaz inhibisyon, anti-ksantin oksidaz (XO) ve antioksidan aktiviteleri incelendi. Bazı bileşiklerin önemli derecede antioksidan aktivite gösterdiği tespit edildi. Özellikle, bileşik 4, 5a, 5b, 5c, 5d ve 6b ABTS•+ radikal katyon temizleme (SC 50 : 9.51-70.43 μg/mL) ve bakır indirgeyici antioksidan kapasite (CUPRAC) tayininde yüksek derecede aktivite gösterdiği belirlendi. Bileşik 6d ise, 125 μg/mL derişimde en yüksek anti-ksantin oksidaz (XO) aktivitesi gösterdi. Bütün bileşikler Jack Bean üreaz aktivite tayin yöntemine göre incelendi ve en aktif üreaz inhibisyonuna sahip bileşiğin 7.41±0.13 μg/mL IC 50 değeriyle (5b) olduğu tespit edildi.